Progress in SiC Bulk Growth

Macroscopic Approach to the Nucleation and Propagation of Foreign Polytype Inclusions during Seeded Sublimation Growth of Silicon Carbide

“…The other two (circles 2 and 3 in Figure 2a) are thin 15R−SiC lamellae, i.e., they do not expand axially in the [000-1] direction. Once formed on the facet, inclusions expand laterally following the step propagation toward the [11][12][13][14][15][16][17][18][19][20] direction and spread all along the crystal diameter. A higher magnification picture of inclusions 1−3 is shown in Figures 2b−d.…”

“…The consequence is the occurrence of two (000-1) facets at both sides of the section. On the right-hand side facet, three 6H−SiC thin lamellae nucleate, indicated by circles 1−3 (Figure 3a), and expand toward the [11][12][13][14][15][16][17][18][19][20] direction. On the left-hand side facet, a thick 15R−SiC inclusion nucleates (left side of Figure 3).…”

“…To resolve the geometrical evolution of the crystal, we quantified both normal (along the [000-1] direction) and lateral (along the [11][12][13][14][15][16][17][18][19][20] direction) growth rates. Also, the lateral propagation of the polytype inclusions (A1−A3 and B1− B3 for inclusions 1−3 of crystals A and B, respectively) was systematically evaluated.…”

“…First, it is worth specifying that each marked interface corresponds to a process time isovalue. The lateral growth rate was thus calculated by the inplane distance (along the [11][12][13][14][15][16][17][18][19][20] direction) covered by the inclusion edge between two marked interfaces, i.e., two time marks. This can be measured only where inclusions are present.…”

“…For crystal B, the growth rate ratio is close to 0.5 at the beginning and progressively increases to reach 1.4 after 15 h. The growth interface is thus concave at the beginning and then progressively flattens and turns slightly convex at the very end of growth. The lateral growth rate along the [11][12][13][14][15][16][17][18][19][20] direction is around 1 order of magnitude higher than the axial growth rate in the [000-1] direction (Figure 4b). Also, the lateral growth rate shows much larger variations than the axial growth rate.…”